| /******************************************************************************* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| *******************************************************************************/ |
| package org.ofbiz.base.concurrent; |
| |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Set; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.FutureTask; |
| import java.util.concurrent.locks.Condition; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| import org.ofbiz.base.lang.LockedBy; |
| import org.ofbiz.base.lang.SourceMonitored; |
| |
| @SourceMonitored |
| public class DependencyPool<K, I extends DependencyPool.Item<I, K, V>, V> { |
| private final Executor executor; |
| private final ConcurrentMap<K, I> allItems = new ConcurrentHashMap<K, I>(); |
| private final ConcurrentMap<K, Future<V>> results = new ConcurrentHashMap<K, Future<V>>(); |
| private final ReentrantLock submitLock = new ReentrantLock(); |
| private final Condition submitCondition = submitLock.newCondition(); |
| @LockedBy("submitLock") |
| private final Set<I> outstanding = new HashSet<I>(); |
| @LockedBy("submitLock") |
| private final List<I> pending = new LinkedList<I>(); |
| |
| public DependencyPool(Executor executor) { |
| this.executor = executor; |
| } |
| |
| public void add(I item) { |
| if (allItems.putIfAbsent(item.getKey(), item) == null) { |
| submitLock.lock(); |
| try { |
| pending.add(item); |
| } finally { |
| submitLock.unlock(); |
| } |
| } |
| } |
| |
| public void addAll(Collection<I> items) { |
| for (I item: items) { |
| add(item); |
| } |
| } |
| |
| public void start() { |
| submitLock.lock(); |
| try { |
| submitWork(); |
| } finally { |
| submitLock.unlock(); |
| } |
| } |
| |
| public V getResult(I item) throws InterruptedException, ExecutionException { |
| Future<V> future = results.get(item.getKey()); |
| if (future == null) { |
| return null; |
| } else { |
| return future.get(); |
| } |
| } |
| |
| public int getResultCount() { |
| return results.size(); |
| } |
| |
| public boolean await() throws InterruptedException { |
| submitLock.lock(); |
| try { |
| submitWork(); |
| while (!outstanding.isEmpty()) { |
| submitCondition.await(); |
| } |
| return pending.isEmpty(); |
| } finally { |
| submitLock.unlock(); |
| } |
| } |
| |
| @LockedBy("submitLock") |
| private int submitWork() { |
| Iterator<I> pendingIt = pending.iterator(); |
| int submittedCount = 0; |
| OUTER: |
| while (pendingIt.hasNext()) { |
| I item = pendingIt.next(); |
| for (K dep: item.getDependencies()) { |
| if (!results.containsKey(dep)) { |
| continue OUTER; |
| } |
| } |
| submittedCount++; |
| pendingIt.remove(); |
| outstanding.add(item); |
| executor.execute(new ItemTask(item)); |
| } |
| return submittedCount; |
| } |
| |
| private class ItemTask extends FutureTask<V> { |
| private final I item; |
| |
| protected ItemTask(I item) { |
| super(item); |
| this.item = item; |
| } |
| |
| @Override |
| protected void done() { |
| super.done(); |
| results.put(item.getKey(), this); |
| submitLock.lock(); |
| try { |
| outstanding.remove(item); |
| if (submitWork() == 0 && outstanding.isEmpty()) { |
| submitCondition.signal(); |
| } |
| } finally { |
| submitLock.unlock(); |
| } |
| } |
| } |
| |
| public interface Item<I extends Item<I, K, V>, K, V> extends Callable<V> { |
| K getKey(); |
| Collection<K> getDependencies(); |
| } |
| } |